Here is an item that will guarantee some laughs. It's the perfect finale for a sponge ball routine that is slightly edgier than the usual fare.

Here the magician shows what appears to be 4 red sponge balls and places them into a spectator's hand and closes the hand. The magician then asks the spectator to concentrate on the sponge balls. When the spectator's hand opens, the 4 sponge balls have turned into...um...uh...well there are two sponge balls and...something else.
NOT RECOMMENDED FOR CHILDREN!